Disclosed are methods of attracting Drosophila suzukii, involving treating an object or area with a Drosophila suzukii attracting effective amount of a composition containing acetoin and at least one compound selected from ethyl octanoate, acetic acid, ethyl acetate, phenethyl alcohol, or mixtures thereof; wherein said composition does not contain ethanol.
The spotted wing drosophila (SWD), Drosophila suzukii Matsumura (Diptera: Drosophilidae), is an invasive fruit-infesting fly native to Southeast Asia (Calabria, G., et al., J. Appl. Entomol., 136: 139-147 (2010)). Since it was accidently introduced to the United States in August in California in 2008, D. suzukii has rapidly spread across the United States and has been detected in a total of 41 states from CA to ME, as well as Canada, Mexico and Europe (Hauser, M., Pest Manage. Sci., 67: 1352-1357 (2011)). D. suzukii attacks a wide variety of fruit and has become a devastating pest of soft-skinned fruit crops, such as raspberries, blueberries, cherries, and strawberries, etc. (Hauser 2011; Beers, E. H., et al., Pest Manage. Sci., 67: 1386-1395 (2011)). Unlike most drosophilid flies that feed and oviposit on overripe fruit, D. suzukii can feed and oviposit on ripening fruit (Calabria et al. 2010; Mitsui, H., et al., Popul. Ecol., 48: 233-237 (2006)). The females possess a serrated ovipositor to cut through the epicarp of their hosts. Fruit infestation by D. suzukii larvae has resulted in significant financial losses to farmers (Walsh, D. B., et al., J. Integr. Pest Manage., 2: G1-G7 (2011); Cini, A., et al., Bull. Insectol., 65: 149-160 (2012)).
Due to its economic impact on fruit crops, farmers usually resort to calendar-based applications of insecticides to manage D. suzukii (Beers et al. 2011; Goodhue, R. E., et al., Pest Manage. Sci., 67: 1396-1402 (2011); Lee, J. C., et al., Pest Manage. Sci. 67, 1349-1351 (2011)). Early detection of this fly on farms is essential for quick management measures, which could lead to reductions in the rate and amount of insecticide applications required to avoid economic loss. To date, SWD populations are monitored by traps that employ fermentation products such as apple cider vinegar (ACV), wine, or yeast as baits (Beers et al. 2011; Lee, J. C., et al., Environ. Entomol., 42, 1348-1355 (2013); Lee, J. C. et al., J. Econ. Entomol., 105: 1350-1357 (2012); Landolt, P. J., et al., J. Appl. Entomol., 136: 148-154 (2012); Landolt, P. J., et al., Fla. Entomol., 95: 326-332 (2012); Kleiber, J. R., et al., Environ. Entomol., 43: 439-447 (2014)). In particular, apple cider vinegar is commonly used because it is easily available and is relatively cheap (Beers et al. 2011; Lee et al. 2011; Lee et al. 2013; Lee et al. 2012). However, apple cider vinegar is not selective; in a study testing different trap designs using apple cider vinegar as bait it was found that only 26-31% of the total numbers of Drosophila spp. caught in traps were D. suzukii (Lee et al. 2012). In addition, ACV baited traps are ineffective at detecting flies before populations reach an economic injury level, leaving farmers without sufficient time to apply protective treatments. Although an 11-component chemical blend based on raspberry volatiles, and a 8-component blend and a 4-component blend based on wine volatiles have been reported as SWD attractants, they are unsatisfactory for the demands of SWD infestation detection and population monitoring because of poor selectivity and efficiency (Abraham, J., et al., Environ. Entomol., 44: 356-367 (2015); Cha, D., et al., J. Chem. Ecol., 38: 1419-1431 (2012); Cha, D. H., et al., Pest Manage. Sci., 70: 324-331 (2014); Cha, D. H., et al., Entomol. Exp. Appl., 154: 251-260 (2015)).
Thus more effective and selective attractants are needed for detecting, monitoring, and managing this invasive species, especially in early season prior to fruit injury. Herein we report such effective attractants for D. suzukii. 